Applying the arrays


All about arrays

Optune Gio delivers therapy through 4 adhesive patches, called transducer arrays. These arrays are applied to your scalp.

Kim, an Optune Gio user and Patient Ambassador

How do I place the arrays?

Watch this video for a step-by-step guide on how to apply arrays, or you can read the steps below.

Preparing your skin

Applying the arrays

Removing the arrays

“The first time I did it, I was pretty nervous. But I was determined I was going to make it work. After that, I just know where the arrays go and I don’t worry so much about that eighth of an inch or quarter-inch that some people may worry about.”

– Sherry, Optune Gio user and Patient Ambassador

How often should I change the arrays?

Transducer arrays must be changed at least 2 times per week (one set of arrays should not be worn for more than 4 days at a time). However, more frequent transducer array changes are recommended if:

The weather has been warmer, causing you to sweat more
Your hair grows quickly. As your hair grows, it prevents the arrays from making good contact with your scalp
You’ve performed intense physical activity, causing you to sweat more
You’re experiencing discomfort, intense itching, or lots of oiliness on your scalp
The hydrogel layer over the ceramic discs becomes soft or “gooey” because of lots of moisture on your scalp

Time-saving tips for array changes

  • Prep the arrays ahead of time so they’re ready to be placed
  • Create an array change area in your home so that all of your supplies can live in one place

Array Management

Learn about managing arrays from those who have firsthand experience.

Caring for your skin
Get skin care tips
Optune Gio evening routine
Get tips from users
Optune Gio Buddy Program
Schedule a chat

Important Safety Information

What is Optune Gio® approved to treat?

Optune Gio is a wearable, portable, FDA-approved device indicated to treat a type of brain cancer called glioblastoma multiforme (GBM) in adult patients 22 years of age or older.

Newly diagnosed GBM

If you have newly diagnosed GBM, Optune Gio is used together with a chemotherapy called temozolomide (TMZ) if:

  • Your cancer is confirmed by your healthcare professional AND
  • You have had surgery to remove as much of the tumor as possible

Recurrent GBM

If your tumor has come back, Optune Gio can be used alone as an alternative to standard medical therapy if:

  • You have tried surgery and radiation and they did not work or are no longer working AND
  • You have tried chemotherapy and your GBM has been confirmed by your healthcare professional

Who should not use Optune Gio?

Optune Gio is not for everyone. Talk to your doctor if you have:

  • An implanted medical device (programmable shunt), skull defect (missing bone with no replacement), or bullet fragment. Optune Gio has not been tested in people with implanted electronic devices, which may cause the devices not to work properly, and Optune Gio has not been tested in people with skull defects or bullet fragments, which may cause Optune Gio not to work properly 
  • A known sensitivity to conductive hydrogels (the gel on the arrays placed on the scalp like the ones used on EKGs). When Optune Gio comes into contact with the skin, it may cause more redness and itching or may rarely cause a life-threatening allergic reaction

Do not use Optune Gio if you are pregnant or are planning to become pregnant. It is not known if Optune Gio is safe or effective during pregnancy.

What should I know before using Optune Gio?

Optune Gio should only be used after receiving training from qualified personnel, such as your doctor, a nurse, or other medical staff who have completed a training course given by Novocure®, the maker of Optune Gio.

  • Do not use any parts that did not come with the Optune Gio Treatment Kit sent to you by Novocure or given to you by your doctor
  • Do not get the device or transducer arrays wet
  • If you have an underlying serious skin condition on the scalp, discuss with your doctor whether this may prevent or temporarily interfere with Optune Gio treatment

What are the possible side effects of Optune Gio?

Most common side effects of Optune Gio when used together with chemotherapy (temozolomide, or TMZ) were low blood platelet count, nausea, constipation, vomiting, tiredness, scalp irritation from the device, headache, seizure, and depression. The most common side effects when using Optune Gio alone were scalp irritation (redness and itchiness) and headache. Other side effects were malaise, muscle twitching, fall and skin ulcers. Talk to your doctor if you have any of these side effects or questions.


Please click here for the Optune Gio Instructions For Use (IFU) for complete information regarding the device’s indications, contraindications, warnings, and precautions.

Novocure Websites

This website is intended for people seeking information on Optune Gio.

On this site, videos and images identified as Optune Gio users, caregivers, or healthcare professionals depict actual patients, caregivers, and healthcare professionals.

Patient images reflect the health status of the patients at the time each photo or video was taken.


All rights reserved.

MyLink, MyNovocure, Novocure, and Optune Gio are registered trademarks of Novocure GmbH.

All other trademarks, registered or unregistered, are the property of their respective owners.

US-OPG-00063 v2.0 March 2024